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-rw-r--r--utils/jztool/src/identify_file.c170
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diff --git a/utils/jztool/src/identify_file.c b/utils/jztool/src/identify_file.c
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+++ b/utils/jztool/src/identify_file.c
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+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2021 Aidan MacDonald
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "jztool.h"
+#include <string.h>
+
+/* Following is copied from mkspl-x1000, basically */
+struct x1000_spl_header {
+ uint8_t magic[8];
+ uint8_t type;
+ uint8_t crc7;
+ uint8_t ppb;
+ uint8_t bpp;
+ uint32_t length;
+};
+
+static const uint8_t x1000_spl_header_magic[8] =
+ {0x06, 0x05, 0x04, 0x03, 0x02, 0x55, 0xaa, 0x55};
+
+static const size_t X1000_SPL_HEADER_SIZE = 2 * 1024;
+
+static uint8_t crc7(const uint8_t* buf, size_t len)
+{
+ /* table-based computation of CRC7 */
+ static const uint8_t t[256] = {
+ 0x00, 0x09, 0x12, 0x1b, 0x24, 0x2d, 0x36, 0x3f,
+ 0x48, 0x41, 0x5a, 0x53, 0x6c, 0x65, 0x7e, 0x77,
+ 0x19, 0x10, 0x0b, 0x02, 0x3d, 0x34, 0x2f, 0x26,
+ 0x51, 0x58, 0x43, 0x4a, 0x75, 0x7c, 0x67, 0x6e,
+ 0x32, 0x3b, 0x20, 0x29, 0x16, 0x1f, 0x04, 0x0d,
+ 0x7a, 0x73, 0x68, 0x61, 0x5e, 0x57, 0x4c, 0x45,
+ 0x2b, 0x22, 0x39, 0x30, 0x0f, 0x06, 0x1d, 0x14,
+ 0x63, 0x6a, 0x71, 0x78, 0x47, 0x4e, 0x55, 0x5c,
+ 0x64, 0x6d, 0x76, 0x7f, 0x40, 0x49, 0x52, 0x5b,
+ 0x2c, 0x25, 0x3e, 0x37, 0x08, 0x01, 0x1a, 0x13,
+ 0x7d, 0x74, 0x6f, 0x66, 0x59, 0x50, 0x4b, 0x42,
+ 0x35, 0x3c, 0x27, 0x2e, 0x11, 0x18, 0x03, 0x0a,
+ 0x56, 0x5f, 0x44, 0x4d, 0x72, 0x7b, 0x60, 0x69,
+ 0x1e, 0x17, 0x0c, 0x05, 0x3a, 0x33, 0x28, 0x21,
+ 0x4f, 0x46, 0x5d, 0x54, 0x6b, 0x62, 0x79, 0x70,
+ 0x07, 0x0e, 0x15, 0x1c, 0x23, 0x2a, 0x31, 0x38,
+ 0x41, 0x48, 0x53, 0x5a, 0x65, 0x6c, 0x77, 0x7e,
+ 0x09, 0x00, 0x1b, 0x12, 0x2d, 0x24, 0x3f, 0x36,
+ 0x58, 0x51, 0x4a, 0x43, 0x7c, 0x75, 0x6e, 0x67,
+ 0x10, 0x19, 0x02, 0x0b, 0x34, 0x3d, 0x26, 0x2f,
+ 0x73, 0x7a, 0x61, 0x68, 0x57, 0x5e, 0x45, 0x4c,
+ 0x3b, 0x32, 0x29, 0x20, 0x1f, 0x16, 0x0d, 0x04,
+ 0x6a, 0x63, 0x78, 0x71, 0x4e, 0x47, 0x5c, 0x55,
+ 0x22, 0x2b, 0x30, 0x39, 0x06, 0x0f, 0x14, 0x1d,
+ 0x25, 0x2c, 0x37, 0x3e, 0x01, 0x08, 0x13, 0x1a,
+ 0x6d, 0x64, 0x7f, 0x76, 0x49, 0x40, 0x5b, 0x52,
+ 0x3c, 0x35, 0x2e, 0x27, 0x18, 0x11, 0x0a, 0x03,
+ 0x74, 0x7d, 0x66, 0x6f, 0x50, 0x59, 0x42, 0x4b,
+ 0x17, 0x1e, 0x05, 0x0c, 0x33, 0x3a, 0x21, 0x28,
+ 0x5f, 0x56, 0x4d, 0x44, 0x7b, 0x72, 0x69, 0x60,
+ 0x0e, 0x07, 0x1c, 0x15, 0x2a, 0x23, 0x38, 0x31,
+ 0x46, 0x4f, 0x54, 0x5d, 0x62, 0x6b, 0x70, 0x79
+ };
+
+ uint8_t crc = 0;
+ while(len--)
+ crc = t[(crc << 1) ^ *buf++];
+ return crc;
+}
+
+/** \brief Identify a file as an SPL for X1000 CPUs
+ * \param data File data buffer
+ * \param len Length of file
+ * \return JZ_SUCCESS if file looks correct, or one of the following errors
+ * \retval JZ_IDERR_WRONG_SIZE file too small or size doesn't match header
+ * \retval JZ_IDERR_BAD_HEADER missing magic bytes from header
+ * \retval JZ_IDERR_BAD_CHECKSUM CRC7 mismatch
+ */
+int jz_identify_x1000_spl(const void* data, size_t len)
+{
+ /* Use <= check because a header-only file is not really valid,
+ * it should have at least one byte in it... */
+ if(len <= X1000_SPL_HEADER_SIZE)
+ return JZ_IDERR_WRONG_SIZE;
+
+ /* Look for header magic bytes */
+ const struct x1000_spl_header* header = (const struct x1000_spl_header*)data;
+ if(memcmp(header->magic, x1000_spl_header_magic, 8))
+ return JZ_IDERR_BAD_HEADER;
+
+ /* Length stored in the header should equal the length of the file */
+ if(header->length != len)
+ return JZ_IDERR_WRONG_SIZE;
+
+ /* Compute the CRC7 checksum; it only covers the SPL code */
+ const uint8_t* dat = (const uint8_t*)data;
+ uint8_t sum = crc7(&dat[X1000_SPL_HEADER_SIZE], len - X1000_SPL_HEADER_SIZE);
+ if(header->crc7 != sum)
+ return JZ_IDERR_BAD_CHECKSUM;
+
+ return JZ_SUCCESS;
+
+}
+
+static const struct scramble_model_info {
+ const char* name;
+ int model_num;
+ size_t offset_crc;
+ size_t offset_name;
+ size_t offset_data;
+} scramble_models[] = {
+ {"fiio", 114, 0, 4, 8},
+ {"shq1", 115, 0, 4, 8},
+ {"eros", 116, 0, 4, 8},
+ {NULL, 0, 0, 0, 0},
+};
+
+/** \brief Identify a file as a Rockbox `scramble` image
+ * \param data File data buffer
+ * \param len Length of file
+ * \return JZ_SUCCESS if file looks correct, or one of the following errors
+ * \retval JZ_IDERR_UNRECOGNIZED_MODEL unsupported/unknown model type
+ * \retval JZ_IDERR_BAD_CHECKSUM checksum mismatch
+ */
+int jz_identify_scramble_image(const void* data, size_t len)
+{
+ const uint8_t* dat;
+ const struct scramble_model_info* model_info;
+ uint32_t sum, file_sum;
+
+ dat = (const uint8_t*)data;
+ model_info = &scramble_models[0];
+
+ /* Look up the model number */
+ for(; model_info->name != NULL; ++model_info) {
+ if(model_info->offset_name + 4 > len)
+ continue;
+ if(!memcmp(&dat[model_info->offset_name], model_info->name, 4))
+ break;
+ }
+
+ if(model_info->name == NULL)
+ return JZ_IDERR_UNRECOGNIZED_MODEL;
+
+ /* Compute the checksum */
+ sum = model_info->model_num;
+ for(size_t i = model_info->offset_data; i < len; ++i)
+ sum += dat[i];
+
+ /* Compare with file's checksum, it's stored in big-endian form */
+ dat += model_info->offset_crc;
+ file_sum = (dat[0] << 24) | (dat[1] << 16) | (dat[2] << 8) | dat[3];
+ if(sum != file_sum)
+ return JZ_IDERR_BAD_CHECKSUM;
+
+ return JZ_SUCCESS;
+}